This invention relates generally to systems and methods for distinguishing a frequency of interest from noise and more particularly to systems and methods for recovering a signal of interest from a complex signal.
Electric machines, such as motors, are used for a wide variety of applications including but not limited to closing or opening electric switches, and/or providing power to electrical appliances. Knowing the frequency of interest with which such electrical machines operate facilitates accurately determining whether a machine is malfunctioning. However, because of surrounding noise, it may be difficult to determine the frequency of interest. Moreover, in some instances, the frequency of interest cannot be easily separated from the noise when the frequency of interest is indistinguishable from the noise.
To facilitate determining the frequency of interest of a machine, at least some applications use a filter to narrow a range of frequencies of operation of the machine to a band of frequencies that includes the frequency of interest. After the operations frequency range is narrowed, the frequency of interest may then be detected from within the frequency band. However, when the signal of interest is indistinguishable from the noise, all spectrum peaks may represent frequencies of the noise rather than the frequency of interest. Selecting one of the spectrum peaks may produce random results, rather than the frequency of interest. Thus, it is difficult to distinguish the frequency of interest from within the frequency band.